The disclosed embodiments relate to a medical device. Specifically, the disclosed embodiments relate to a balloon catheter.
Balloon catheters, which are used for expanding a stenosis site and the like in a lumen such as a blood vessel, are traditionally known.
A balloon catheter mainly comprises a balloon as an expanding object, an outer tube attached to a proximal end portion of the balloon, and an inner tube disposed inside an inner cavity of the outer tube and having a distal end portion attached to a distal end portion of the balloon.
The outer tube is designed for allowing an expansion liquid such as physiological saline to flow through a cavity defined between the outer tube and the inner tube in order to expand the balloon. The inner tube is designed so that a guide wire may be inserted into the inner tube in order to guide the balloon catheter to an affected area.
In general, a balloon catheter is used as follows: an operator such as a physician holds the balloon catheter at a proximal end portion of the balloon catheter and pushes a distal end portion of the balloon catheter into a blood vessel. Therefore, in order to position the balloon in a desired location of an affected area, excellent pushability into the affected area and excellent maneuverability of the distal portion are required.
Japanese Patent Application Laid-Open No. 2012-20077 describes a balloon catheter comprising a core wire inserted between a catheter shaft (an outer tube) and an inner shaft (an inner tube) in addition to the configuration described above, wherein the core wire is sandwiched between the outer tube and the inner tube.
According to Japanese Patent Application Laid-Open No. 2012-20077, the balloon catheter can supposedly improve the pushability of the balloon catheter without the need for a complicated process by simply sandwiching the core wire between the outer tube and the inner tube.
However, the balloon catheter described in Japanese Patent Application Laid-Open No. 2012-20077 has the following problems. Although the pushability of the catheter may be improved, in a case where the proximal end portion of the balloon catheter is pulled, the resulting pulling force cannot be transmitted to the balloon catheter through the core wire. Further, in a case where a pushing force against the proximal end portion of the balloon catheter is very strong, the core wire will move between the outer tube and the inner tube in the distal direction. Therefore, the core wire will be fixed between the outer tube and the inner tube, interfering with the flexibility of the balloon catheter.